Heart-lung apparatus



A. E. cHEsLl-:R 2,652,831

HEART-LUN@ APPARATUS Filed Jan. 31, 1952 ria-iz @9' Sept. 22, 1953 JNVENTOR. 45k/:HAM E @man /17' 70k/VE Y Patented Sept. 22, 1953 UNITEDsTA'rizA sassi ENT oFFicE 1 This invention relates to apparatus forproviding an eXtra-corporeal blood circuit for humans and other animalsas during surgery ofthe heart and when it is desirable to halt the heartaction. Prior attempts to provide such apparatus have shown thatanatomical limitations dictate n the impracticability of by-passing theheart only.

Hence, research has been along a line seeking Y apparatus that performsnot only the pumping function of the heart but also the 'oxygenatingfunction of the lungs. Accordingly, the present apparatus comprises aheart-lung machine that induces rhythmic circulation of the blood inabody while simultaneously and alternately drawing olf carbon dioxidefrom the venous blood and replacing the same with oxygen, therebyproviding suitably oxygenated arterial blood to the body.

An object of the present invention is to p-rovide a heart-lung machinethat functions to provide a closed blood-circulating system to, thereby,eliminate introduction into the circulation of foreign bodies orelements which may contaminate the blood stream.

Another object of the invention vis to provide apparatus of theVcharacter described that em'- bodies simple, improved and effectivemeans for' oxygenating the'blood'being circulated, the same entailingthe alternate application of vacuum and introduction of oxygen underpressure in contradistinction to prior mechanical devices that film orattenuate the blood in the undepen'dlable expectation that the same willabsorb suIi-` cient oxygen.

VA further object of the invention is to provide a heart-lung apparatusthat has high oxygenating eiiciency coupled with a minimum of foaming(which may result in loss of blood), and a minimum of hemolysis or otherdamage and/or dilution of the blood cells of the blood stream.

Another object of the invention is to provide heart-lung apparatus inwhich the receptacles or vessels and the conduits or tubes thatcirculate the blood are adapted for Veasy sterilization by steam orother recognized and readily available media. l

The invention comprises novel details of construction and novelcombinations and arrangements of parts, which will more fully appear inthe course of the following description and which is based on theaccompanying drawing. However, the drawing merely shows and thedescription merely describesone embodiment of the invention, which i'sgiven by way of example or illustration only.

In the drawing:

Fig. 1 is a systematic view showing the present apparatus, severalcomponents thereof being shown in section. i

Fig. 2 is an end view of cam means employed in the invention tosynchronize the functionof the apparatus.

The present vapparatus is connected Vin the blood stream 'of a body byinserting a cannula, connected'to tube 5, in theinferior vena cava, andinserting a cannula, connected to tube into the left supercial femoralartery. Since this artery leads to the aorta,'it will be seen from thefollowing description that venous blood is drawn from the vena cavavinto the apparatus, oxygen-i ated in said apparatus, and, in suitablepulsations; discharged into vthe femoral artery to, thereby, establish aclosed blood-circulating system. It should beunderstood that the bodyconnections may be varied, providing tube 5 has a venal connection vandVtube S an arterial connection, without affectingthe function of; theapparatus. 1 p g The present apparatus comprises, generally,V anoXygenatingunit-l, a-stabilizing unit 8 lconnected in series with unit'I and discharging into tube 5, a source vof negative pressure orVacuum-,9, a source of oxygen under pressure le, valve means I I toalternately operatively connect unit 'l to the vacuum andoxygenrsources, and means I2 to control the valve means. I

Unit 1 is shown as comprising an enclosed receptacle or Yvessel "I3,preferably made of glass, and provided with three downwardly directed`ports I4, I Sand I5." Port I d is controlled by a check valve I1 thatchecks flow from receptacle I3 and permits flow thereinto. Port I5 'iscontrolled by a check valve I8 similar yto valve Il and also checks nowfrom the receptacle and permits flow thereinto. Port I 6' isv controlledby a check valve I9 that checks flow into receptacle i3 and permits flowtherefrom.

At the top, or at least above the level of a quantity of blood 20 inreceptacle I3, an vinlet port 2| is provided,-as well asa pressurerelieiC or safety valve 22, an inlet 23 for replenishing blood from areserve, and a gauge 24thatindicates the vacuum-pressure fluctuationsinsaid receptable.

Unit 8 is shown as van enclosed glass receptacle` 25 somewhat smaller incapacity than receptacle I3. Receptacle 25 isprovided with twodownwardly directed vports 26 andk 2l and, above the level Aof blood28ltherein, saidV receptacle is provided with a relief or Safety valvea,an inlet 29 for'replenishing blood from a reserve, andan inlet 30 forsecondary oxygen,

The source of vacuum 9 may comprise any conn ventional means such as asuction pump and the same is connected to a tube or pipe 3l, the new inwhich is controlled as by a solenoid valve In practice, the degree ofVacuum is approximately fifteen inches of mercury. The source of xygen Imay comprise a tank of said gas conventionally valve controlled tosupply oxygen at approximately iifteen pounds to tube or pipe 33. Asclenoid valve 34 controls flow in the latter pipe.

Valve means II comprises, generally, two similar valves 35 and 35, cammeans 31 controlling said valves, and a drive 38 for the cam means.

Valves 35 and 36 are shown as of the reciproeating type. Each comprisesa cylinder 39, a piston 4G operating in said cylinder, and a stem 4Iextending from the piston beyond one end of the cylinder. Each piston55, on its opposite faces, is provided with a compressible sealing disc42. An expansion spring 43, in a hollow provided in each stem 4I, bearsagainst an end wall 44 of each cylinder to normally project the pistonsaway from their respective walls I4 and allow inter-communication ofports 35 and l5 in wall 44 of valve 35, and of ports 3l, I8 and 49 inwall 44 of valve 35.

From the foregoing it will be clear that, when spring 43 is eiective toproject piston 55 away from wall 44 of either valve, the ports in saidwall are in communication through cylinder 39 while one disc 42 sealsagainst cylinder abutment 53 and, that when piston 4B is moved againstthe force of spring 43 to press the opposite disc 42 against wall 44,the ow between the respective ports in said valves is shut off. It willbe noted that the faces of discs 42 seal at the ends or the pistonstrokes while the edges thereof seal against the cylindrical walls ofcylinders 33 to prevent leakage past the pistons during the strokes. Inthe usual way, each cylinder is pro vided with a vent I to relievecounteracting back-pressure on the pistons.

Cam means 31 controls reciprocation of pistons 39 so that, as one isprojected, the other is retracted. Thus, when ports 45 and 55 are incommunication, ports 41, 43 and 49 are closed to flow and vice versa. Inthe present case, means 3l comprises cams 52 and 53 on a common shaft 54and relatively phased 180, the cams being in respective operativeengagement with the stems 4I of valves 35 and 36. As seen from Fig. 2,only one of said cams, at any one time, is engaged to close one valve,the other valve being held open by the spring 43 therein. Slightvariations in the phasing of cams 52 and 53 may be effected byrotational adjustment thereof on shaft 54 so that valves 35 and 35 maybe timed or synchronized as desired.

Drive 38 may operate at a speed to alternately open and close valves 35and 36 according to a desired pulse rate. In practice, shaft 54 isdriven at approximately 68 R. P. M. as by an electric motor 55 and aspeed reducer unit 55 of which shaft 54 is the output.

Tube 5 is connected to port I4 to supply venous blood to receptacle I3.A tube 51 connects ports I6 and 2E to transfer blood from receptacle I3to receptacle 25, a flow-controlling clamp 53 being applied to saidtube. Tube 5 is connected to port 21 and is controlled by a clamp 59. Aiiow meter 60 is provided in tube 5 to show the rate of ow in said tubeas regulated by clamp 59. If desired, the temperature of the bloodflowing in tube 6 may be regulated as by a heating device 6I.

Tube 3l is connected to port 45 of valve 35, and tube 33 to port 41 ofvalve 36. A tube 52 connects ports I5 and 48 and iiow in the latter tubeis regulated by a clamp 63.

A tube 54, connected to port 2l, is divided into branches 55 and 55 andsaid branches are connected to ports 45 and 49, respectively. Branch 55is provided with a flow-regulating clamp 61.

Operation After a suitable amount of donors blood is placed inreceptacles I3 and 25 through the respective inlets 23 and 29, saidinlets are plugged or otherwise closed. Motor 55 is started and, at thesame time, valves 32 and 34 are opened, simultaneously.

Assuming the positions of valves 35 and 3B as shown, the oxygen flow isclosed and receptacle I3 is subjected to vacuum from source 9. Thissuction opens valve I'l while closing valve I9 and draws venous bloodfrom tube 5 into the receptacle. Since he pressure in said receptacle isnow below atmospheric, the blood therein releases contained gases,particularly carbon dioxide, said gases nrst being drawn into therrareiied atmosphere above blood 25 andY then outward through tubes 64,55 and 3|. This condition continues during the period that valve 35 isopen, or one-half rotation of shaft 54.

When cam 52 closes valve 35 and cam 53 substantially simultaneouslyopens valve 36, the vacuum to receptacle I3 is shut orf and theatmosphere above the blood therein is supplied with oxygen from sourceIIB through tubes 33, 55 and 55. upwardly through blood 25 from tube 52and past valve I3 which is opened by the pressure oi the oxygen now.Some of the carbon dioxide, if not previously removed by the vacuum,will be displaced by the upwardly bubbling oxygen. In this manner, theblood 25 is thoroughly oxygenated.

As the incoming oxygen builds up the pressure in receptacle I3, valveI'I closes to shut off venous ow and when said pressure increases beyondthat in the stabilizing receptacle 25, valve I9 opens andoxygen-enriched blood flows through tube 5l into said receptacle 25.There may be some bubbles of oxygen in blood 20. However, because of thebottom discharge of port I5, bubble-free blood passes into receptacle25.

The atmosphere in receptacle 25 that is supplied by the secondary oxygenthrough inlet 3S is regulated, in practice, to substantially equalnormal blood pressure. This pressure may be read on gauge 53.Consequently, as pressure iluid from receptacle I3 enters receptacle 25and fluid from the latter receptacle simultaneously discharges throughtube 6, the pressure in re.

ceptacle 25 is stabilized through the medium of the secondary oxygen. Inthis manner, the variable pressure at which blood is delivered toreceptacle 25 is stabilized in said receptacle and, therefore, arterialblood is supplied to and through tube 5 at a substantially uniform anddesired pressure.

The discharge from tube 5 is continuous and at greatest pressure whenvalve 35 is open, the pressure gradually diminishing as the pressure inreceptacle I3 decreases. Clamp valves 53 and 5l control the supply ofoxygen to the blood in receptacle I3 and cla-mp valves 55 and 59 controlthe rate of blood flow between the receptacles and in the vconnection 6to the artery. The

Simultaneously, oxygen percolatesV safety valves 22 and 28a are set torelieve when pressures become too high in the receptacles, and gauge 24,by its teetering pointer, shows the vacuum-pressure cycle of theoperation.

Although the source 9 provides a vacuum of about Hg and source Ml aboutfteen pounds pressure of oxygen, due to the rapid alternatingapplication of vacuum and pressure to receptacle I3, as controlled bythe means l2, such vacuum and pressure in the receptacledo not reach thefull degrees of the sources. At 68 R. P. M. of the cam means, theatmosphere in receptacle I3 varies between approximately five poundsabove atmospheric and 3" Hg vacuum. To insure that such positive andnegative pressures in said receptacle are never exceeded, valves 32 and34 must be opened and closed simultaneously and, therefore, are solenoidcontrolled rather than manually controlled. Thus, the solenoids of saidvalves may be connected in a common electric circuit E0 and one switch'il in said circuit provided to simultaneously energize or deenergizethe solenoids and, thereby, simultaneously open and close valves 32 and34 to avoid excessive build up of oxygen pressure should valve 34 beopened iirst or excessive reduction of vacuum should valve 32 be openedrst. Such common electric control is exemplary of means effectingsimultaneous actuation of valves 32 and 34 It will be seen from theforegoing that unit 'I serves not only as a lung apparatus to oxygenatethe blood and rid the same of carbon dioxide, but also as a heartbecause the vacuum-pressure cycle therein, without the aid of anyoutside pump, sets up a flow of oxygenated blood comparable to the ilowresulting from the pulsations of the heart.

While I have described what I now regard as the preferred form of myinvention, the same, of course, may be varied within the spirit andscope of the invention. Therefore, I do not wish to restrict myself tothe particular form of construction illustrated and described, butdesire to avail myself of all modications of my invention that may fallwithin the scope of the appended claims.

Having thus described my invention, what I claim and desire to obtain byLetters Patent, is:

1. Apparatus of the character described comprising a closed receptacle,a connection to the bottom of said receptacle to conduct venous bloodthereto, means to apply vacuum to said receptacle above the bloodtherein to withdraw carbon dioxide and other gases from said blood anda1- ternately to introduce oxygen under pressure into said blood toreplace the gases withdrawn, a second closed receptacle, a ilowconnection between the bottoms of said receptacles to transfer bloodfrom the first receptacle to the second receptacle under pressure ofsaid oxygen, and a bottom discharge for oxygenated blood from saidsecond receptacle.

2. Apparatus according to claim 1: a connection to the second receptacleabove the level of blood therein to supply secondary oxygen to saidsecond receptacle at a pressure lower than the pressure of the oxygenintroduced into the first receptacle.

3. Apparatus according to claim 1: said vacuum-applying andoxygen-introducing means comprising a valve-controlled vacuum connectionto the first receptacle above the level of blood therein, and a similarvalve-controlled oxygen-conducting connection to both the lowerportionof the latter'receptacle and to a portion thereof above saidblood level.

v 4. Apparatus according to claim l: said vacuum-applying andoxygen-introducing means comprising a valve-controlled vacuum connectionto the first receptacle above the level of blood therein, a similarvalve-controlled oxygen-conducting connection to both the lower portionof the latter receptacle and to a portion thereof above said bloodlevel, and means `to operate the valves of said connections toalternately and synchronously open and close said valves to alternatethe vacuum and the pressure of oxygen in said receptacle. V

5. In apparatus of` the character described, a closed lliquid-containingreceptacle having three downwardly opening ports, a check valvecontrolling one of said ports against ilow into the receptacle, a checkvalve controlling each of the other two ports against flow outward fromthe receptacle, an inlet for oxygen under pressure to the receptacleabove the level of liquid therein, a connection to one of said other twoports to conduct oxygen under pressure to the liquid in said receptacle,a connection for venous blood to the other of said two ports, adischarge connection from the first-mentioned of the three ports, meansintermittently admitting oxygen simultaneously to said inlet and saidoxygenadmitting port, means connected to said inlet to apply vacuum tothe receptacle, and means to synchronize and alternate theoxygen-supplying and vacuum-applying means.

6. In combination, a blood-oxygenating unit, means to alternately applyvacuum to said unit to induce release of gases contained in the bloodtherein and supply oxygen under pressure to said unit to oxygenate theblood after release of said gases, a venous blood connection to thebottom of said unit, a stabilizing unit, a check-valvecontrolledconnection between the units t0 conduct oxygenated blood from theoxygenating unit to the stabilizing unit, a connection for secondaryoxygen to said stabilizing unit to stabilize the pressure in said latterunit, and a discharge connection for oxygenated blood from the latterunit.

7. The combination according to claim 6: the means supplying oxygen tothe oxygenating unit including a conductor discharging directly into theblood in the latter unit and a conductor discharging into said latterunit above the level of blood therein.

8. In combination, a blood-oxygenating unit, means to alternately applyvacuum to said unit to induce release of gases contained in the bloodtherein and supply oxygen under pressure to said unit to oxygenate theblood after release of said gases, a venous blood connection to thebottom of said unit, a stabilizing unit, a check-valvecontrolledconnection between the units to conduct oxygenated blood from theoxygenating unit to the stabilizing unit, a connection for secondaryoxygen to said stabilizing unit to stabilize the pressure in said latterunit, a discharge connection for oxygenated blood from the latter unit,and flow rate controlling means in the checkvalve-controlled connectionand in the discharge connection.

9. In apparatus of the -character described, a closed receptacle, a portin the lower part of the receptacle for admitting blood into thereceptacle, a check valve controlling said port to open to admission ofblood only when the pressure in the receptacle is lowered, a second portin the lower part of the receptacle to admit oxygen under amasarpressure to the blood in the receptacle and to raise the pressure in thereceptacle and on the blood therein, a check Valve controlling saidsecond port to open only to said admission of pressure oxygen, adischarge port in the lower part of the receptacle, a check Valvecontrolling discharge of blood from the latter port and open only whenthe pressure in the receptacle is raised during admission of pressureoxygen, a port in the upper part of the receptacle and above the bloodtherein, and means connected to the last-mentioned port to lower thepressure in the receptacle and connected to the oxygen-admitting port toalternately supply pressure oxygen to the receptacle and raise thepressure therein.

10. In apparatus according to claim 9: said ABRAHAM E. CHESLER.

References Cited in the le of this patent UNITED STATES PATENTS NumberName Date 1,696,496 McMurdo Dec. 25, 1928 1,937,566 Hanan et al Dec. 5,1933 2,406,207 Desmet Aug. 20, 1946 2,474,665 Guarino June 28, 1949

